KVM: s390: Move common code of mem_op functions into function

The vcpu and vm mem_op ioctl implementations share some functionality.
Move argument checking into a function and call it from both
implementations. This allows code reuse in case of additional future
mem_op operations.

Suggested-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Janis Schoetterl-Glausch <scgl@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Link: https://lore.kernel.org/r/20230206164602.138068-9-scgl@linux.ibm.com
Message-Id: <20230206164602.138068-9-scgl@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index cb72f9a09fb3610d75eeade4485f5fbc07a6a729..9645015f5921bfd118e5171cb24a0b69210a561c 100644 (file)
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -2764,24 +2764,32 @@ static int kvm_s390_handle_pv(struct kvm *kvm, struct kvm_pv_cmd *cmd)
        return r;
 }
 
-static bool access_key_invalid(u8 access_key)
+static int mem_op_validate_common(struct kvm_s390_mem_op *mop, u64 supported_flags)
 {
-       return access_key > 0xf;
+       if (mop->flags & ~supported_flags || !mop->size)
+               return -EINVAL;
+       if (mop->size > MEM_OP_MAX_SIZE)
+               return -E2BIG;
+       if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
+               if (mop->key > 0xf)
+                       return -EINVAL;
+       } else {
+               mop->key = 0;
+       }
+       return 0;
 }
 
 static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
 {
        void __user *uaddr = (void __user *)mop->buf;
-       u64 supported_flags;
        void *tmpbuf = NULL;
        int r, srcu_idx;
 
-       supported_flags = KVM_S390_MEMOP_F_SKEY_PROTECTION
-                         | KVM_S390_MEMOP_F_CHECK_ONLY;
-       if (mop->flags & ~supported_flags || !mop->size)
-               return -EINVAL;
-       if (mop->size > MEM_OP_MAX_SIZE)
-               return -E2BIG;
+       r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_SKEY_PROTECTION |
+                                       KVM_S390_MEMOP_F_CHECK_ONLY);
+       if (r)
+               return r;
+
        /*
         * This is technically a heuristic only, if the kvm->lock is not
         * taken, it is not guaranteed that the vm is/remains non-protected.
@@ -2793,12 +2801,6 @@ static int kvm_s390_vm_mem_op(struct kvm *kvm, struct kvm_s390_mem_op *mop)
         */
        if (kvm_s390_pv_get_handle(kvm))
                return -EINVAL;
-       if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
-               if (access_key_invalid(mop->key))
-                       return -EINVAL;
-       } else {
-               mop->key = 0;
-       }
        if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
                tmpbuf = vmalloc(mop->size);
                if (!tmpbuf)
@@ -5250,23 +5252,17 @@ static long kvm_s390_vcpu_mem_op(struct kvm_vcpu *vcpu,
 {
        void __user *uaddr = (void __user *)mop->buf;
        void *tmpbuf = NULL;
-       int r = 0;
-       const u64 supported_flags = KVM_S390_MEMOP_F_INJECT_EXCEPTION
-                                   | KVM_S390_MEMOP_F_CHECK_ONLY
-                                   | KVM_S390_MEMOP_F_SKEY_PROTECTION;
+       int r;
 
-       if (mop->flags & ~supported_flags || mop->ar >= NUM_ACRS || !mop->size)
+       r = mem_op_validate_common(mop, KVM_S390_MEMOP_F_INJECT_EXCEPTION |
+                                       KVM_S390_MEMOP_F_CHECK_ONLY |
+                                       KVM_S390_MEMOP_F_SKEY_PROTECTION);
+       if (r)
+               return r;
+       if (mop->ar >= NUM_ACRS)
                return -EINVAL;
-       if (mop->size > MEM_OP_MAX_SIZE)
-               return -E2BIG;
        if (kvm_s390_pv_cpu_is_protected(vcpu))
                return -EINVAL;
-       if (mop->flags & KVM_S390_MEMOP_F_SKEY_PROTECTION) {
-               if (access_key_invalid(mop->key))
-                       return -EINVAL;
-       } else {
-               mop->key = 0;
-       }
        if (!(mop->flags & KVM_S390_MEMOP_F_CHECK_ONLY)) {
                tmpbuf = vmalloc(mop->size);
                if (!tmpbuf)